Flashing is the method of transitioning or terminating of exterior building components. Metal flashing is typically used at exterior wall opening conditions that employ fenestration components, including but not limited to, windows, doors, storefront, window wall, curtain wall, louvers and building enclosure transitions and terminations of, including but not limited to, cladding, air barriers, weather resistive barriers, waterproofing and roofing. Metal flashing's functional purpose is to provide environmental protection and to divert water away from the building at transitions or terminations of exterior building components. The flashing's aesthetic purpose is to provide an attractive transition or termination of exterior building components. The current method for flashing at exterior wall fenestration openings involves the placing of flashing after the support framing is complete. The flashing is typically secured with mechanical fasteners such as nails or screws that penetrate the flashing. In many cases, the mechanical fasteners secure the flashing at a horizontal and vertical return surfaces of the fenestration opening. The penetrations created by the attachment of the flashing and the attachment are typically sealed with an elastomeric mastic or sealant. Functionally, with the current method, the penetrations for the attachment allow for a point of entry for future air leakage or water penetration when the mastic or sealant fails, is not installed properly or is not installed at all.
Further, flashing is often required to be mounted prior to adjacent exterior building components in order to conceal the mechanical fasteners that are used to attach the metal flashing. This condition limits the ability to modify or replace the metal flashing later without removal of the concealing fenestration and is a thermal bridge. This installation method also limits construction sequencing and can create conditions where the metal flashing is exposed and more prone to damage before the remaining exterior building components can be installed.